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人教版高中数学选修3离散型随机变量及其分布列(1)教学设计
4.写出下列随机变量可能取的值，并说明随机变量所取的值表示的随机试验的结果．(1)一个袋中装有8个红球，3个白球，从中任取5个球，其中所含白球的个数为X.(2)一个袋中有5个同样大小的黑球，编号为1,2,3,4,5，从中任取3个球，取出的球的最大号码记为X.(3). 在本例(1)条件下，规定取出一个红球赢2元，而每取出一个白球输1元，以ξ表示赢得的钱数，结果如何？[解] (1)X可取0,1,2,3.X＝0表示取5个球全是红球；X＝1表示取1个白球，4个红球；X＝2表示取2个白球，3个红球；X＝3表示取3个白球，2个红球．(2)X可取3,4,5.X＝3表示取出的球编号为1,2,3；X＝4表示取出的球编号为1,2,4；1,3,4或2,3,4.X＝5表示取出的球编号为1,2,5；1,3,5；1,4,5；2,3,5；2,4,5或3,4,5.(3) ξ＝10表示取5个球全是红球；ξ＝7表示取1个白球，4个红球；ξ＝4表示取2个白球，3个红球；ξ＝1表示取3个白球，2个红球．
直线的点斜式方程教学设计人教A版高中数学选择性必修第一册
【答案】B [由直线方程知直线斜率为3，令x＝0可得在y轴上的截距为y＝－3.故选B.]3．已知直线l1过点P(2,1)且与直线l2：y＝x＋1垂直，则l1的点斜式方程为________．【答案】y－1＝－(x－2) [直线l2的斜率k2＝1，故l1的斜率为－1，所以l1的点斜式方程为y－1＝－(x－2)．]4．已知两条直线y＝ax－2和y＝(2－a)x＋1互相平行，则a＝________. 【答案】1 [由题意得a＝2－a，解得a＝1.]5.无论k取何值,直线y-2=k(x+1)所过的定点是 . 【答案】(-1,2)6．直线l经过点P(3,4)，它的倾斜角是直线y＝3x＋3的倾斜角的2倍，求直线l的点斜式方程．【答案】直线y＝3x＋3的斜率k＝3，则其倾斜角α＝60°，所以直线l的倾斜角为120°.以直线l的斜率为k′＝tan 120°＝－3.所以直线l的点斜式方程为y－4＝－3(x－3)．
直线的两点式方程教学设计人教A版高中数学选择性必修第一册
解析：①过原点时，直线方程为y＝－34x.②直线不过原点时，可设其方程为xa＋ya＝1，∴4a＋－3a＝1，∴a＝1.∴直线方程为x＋y－1＝0.所以这样的直线有2条，选B.答案：B4.若点P(3,m)在过点A(2,-1),B(-3,4)的直线上,则m= . 解析:由两点式方程得,过A,B两点的直线方程为(y"-(-" 1")" )/(4"-(-" 1")" )=(x"-" 2)/("-" 3"-" 2),即x+y-1=0.又点P(3,m)在直线AB上,所以3+m-1=0,得m=-2.答案:-2 5.直线ax+by=1(ab≠0)与两坐标轴围成的三角形的面积是 . 解析:直线在两坐标轴上的截距分别为1/a 与 1/b,所以直线与坐标轴围成的三角形面积为1/(2"|" ab"|" ).答案:1/(2"|" ab"|" )6.已知三角形的三个顶点A(0,4)，B(－2,6)，C(－8,0)．(1)求三角形三边所在直线的方程；(2)求AC边上的垂直平分线的方程．解析(1)直线AB的方程为y－46－4＝x－0－2－0，整理得x＋y－4＝0；直线BC的方程为y－06－0＝x＋8－2＋8，整理得x－y＋8＝0；由截距式可知，直线AC的方程为x－8＋y4＝1，整理得x－2y＋8＝0.(2)线段AC的中点为D(－4,2)，直线AC的斜率为12，则AC边上的垂直平分线的斜率为－2，所以AC边的垂直平分线的方程为y－2＝－2(x＋4)，整理得2x＋y＋6＝0.
人教版高中数学选修3离散型随机变量的方差教学设计
3.下结论.依据均值和方差做出结论.跟踪训练2. A、B两个投资项目的利润率分别为随机变量X1和X2，根据市场分析， X1和X2的分布列分别为X1 2% 8% 12% X2 5% 10%P 0.2 0.5 0.3 P 0.8 0.2求：(1)在A、B两个项目上各投资100万元， Y1和Y2分别表示投资项目A和B所获得的利润，求方差D(Y1)和D(Y2)；(2)根据得到的结论，对于投资者有什么建议？ 解：(1)题目可知，投资项目A和B所获得的利润Y1和Y2的分布列为：Y1 2 8 12 Y2 5 10P 0.2 0.5 0.3 P 0.8 0.2所以 ;; 解：(2) 由(1)可知 ，说明投资A项目比投资B项目期望收益要高；同时 ，说明投资A项目比投资B项目的实际收益相对于期望收益的平均波动要更大.因此，对于追求稳定的投资者，投资B项目更合适;而对于更看重利润并且愿意为了高利润承担风险的投资者，投资A项目更合适.
直线的一般式方程教学设计人教A版高中数学选择性必修第一册
解析:当a0时,直线ax-by=1在x轴上的截距1/a0,在y轴上的截距-1/a>0.只有B满足.故选B.答案:B 3．过点(1,0)且与直线x－2y－2＝0平行的直线方程是( ) A．x－2y－1＝0 B．x－2y＋1＝0C．2x＋y＝2＝0 D．x＋2y－1＝0答案A 解析：设所求直线方程为x－2y＋c＝0，把点(1,0)代入可求得c＝－1.所以所求直线方程为x－2y－1＝0.故选A.4．已知两条直线y＝ax－2和3x－(a＋2)y＋1＝0互相平行，则a＝________.答案：1或－3 解析：依题意得：a(a＋2)＝3×1，解得a＝1或a＝－3.5．若方程(m2－3m＋2)x＋(m－2)y－2m＋5＝0表示直线．(1)求实数m的范围；(2)若该直线的斜率k＝1，求实数m的值．解析： (1)由m2－3m＋2＝0，m－2＝0，解得m＝2，若方程表示直线，则m2－3m＋2与m－2不能同时为0，故m≠2.(2)由－?m2－3m＋2?m－2＝1，解得m＝0.
人教版高中数学选择性必修二等差数列的前n项和公式（2）教学设计
课前小测1．思考辨析(1)若Sn为等差数列{an}的前n项和，则数列Snn也是等差数列．( )(2)若a1>0，d<0，则等差数列中所有正项之和最大．( )(3)在等差数列中，Sn是其前n项和，则有S2n－1＝(2n－1)an.( )[答案] (1)√ (2)√ (3)√2．在项数为2n＋1的等差数列中，所有奇数项的和为165，所有偶数项的和为150，则n等于( )A．9 B．10 C．11 D．12B [∵S奇S偶＝n＋1n，∴165150＝n＋1n.∴n＝10.故选B项．]3．等差数列{an}中，S2＝4，S4＝9，则S6＝________.15 [由S2，S4－S2，S6－S4成等差数列得2(S4－S2)＝S2＋(S6－S4)解得S6＝15.]4．已知数列{an}的通项公式是an＝2n－48，则Sn取得最小值时，n为________.23或24 [由an≤0即2n－48≤0得n≤24.∴所有负项的和最小，即n＝23或24.]二、典例解析例8.某校新建一个报告厅，要求容纳800个座位，报告厅共有20排座位，从第2排起后一排都比前一排多两个座位. 问第1排应安排多少个座位？分析：将第1排到第20排的座位数依次排成一列，构成数列{an} ，设数列{an} 的前n项和为S_n。
人教版高中数学选择性必修二函数的单调性(1) 教学设计
1．判断正误(正确的打“√”，错误的打“×”)(1)函数f (x)在区间(a，b)上都有f ′(x)＜0，则函数f (x)在这个区间上单调递减． ( )(2)函数在某一点的导数越大，函数在该点处的切线越“陡峭”． ( )(3)函数在某个区间上变化越快，函数在这个区间上导数的绝对值越大．( )(4)判断函数单调性时，在区间内的个别点f ′(x)＝0，不影响函数在此区间的单调性．( )[解析] (1)√ 函数f (x)在区间(a，b)上都有f ′(x)＜0，所以函数f (x)在这个区间上单调递减，故正确．(2)× 切线的“陡峭”程度与|f ′(x)|的大小有关，故错误．(3)√ 函数在某个区间上变化的快慢，和函数导数的绝对值大小一致．(4)√ 若f ′(x)≥0(≤0)，则函数f (x)在区间内单调递增(减)，故f ′(x)＝0不影响函数单调性．[答案] (1)√ (2)× (3)√ (4)√例1. 利用导数判断下列函数的单调性:（1）f(x)=x^3+3x; （2） f(x)=sinx-x,x∈(0,π); (3)f(x)=(x-1)/x解: (1) 因为f(x)=x^3+3x, 所以f^' (x)=〖3x〗^2+3=3(x^2+1)>0所以f(x)=x^3+3x ，函数在R上单调递增，如图（1）所示
人教版高中数学选修3分类变量与列联表教学设计
一、 问题导学前面两节所讨论的变量,如人的身高、树的胸径、树的高度、短跑100m世界纪录和创纪录的时间等,都是数值变量,数值变量的取值为实数.其大小和运算都有实际含义.在现实生活中,人们经常需要回答一定范围内的两种现象或性质之间是否存在关联性或相互影响的问题.例如,就读不同学校是否对学生的成绩有影响,不同班级学生用于体育锻炼的时间是否有差别,吸烟是否会增加患肺癌的风险,等等,本节将要学习的独立性检验方法为我们提供了解决这类问题的方案。在讨论上述问题时,为了表述方便,我们经常会使用一种特殊的随机变量,以区别不同的现象或性质,这类随机变量称为分类变量.分类变量的取值可以用实数表示,例如,学生所在的班级可以用1,2,3等表示,男性、女性可以用1,0表示,等等.在很多时候,这些数值只作为编号使用,并没有通常的大小和运算意义,本节我们主要讨论取值于{0,1}的分类变量的关联性问题.
人教版高中数学选修3二项式系数的性质教学设计
1.对称性与首末两端“等距离”的两个二项式系数相等,即C_n^m=C_n^(n"-" m).2.增减性与最大值 当k(n+1)/2时,C_n^k随k的增加而减小.当n是偶数时,中间的一项C_n^(n/2)取得最大值;当n是奇数时,中间的两项C_n^((n"-" 1)/2) 与C_n^((n+1)/2)相等,且同时取得最大值.探究2.已知(1+x)^n =C_n^0+C_n^1 x+...〖+C〗_n^k x^k+...+C_n^n x^n 3.各二项式系数的和C_n^0+C_n^1+C_n^2+…+C_n^n=2n.令x=1 得(1+1)^n=C_n^0+C_n^1 +...+C_n^n=2^n所以，(a+b)^n 的展开式的各二项式系数之和为2^n1. 在(a+b)8的展开式中,二项式系数最大的项为 ,在(a+b)9的展开式中,二项式系数最大的项为 . 解析:因为(a+b)8的展开式中有9项,所以中间一项的二项式系数最大,该项为C_8^4a4b4=70a4b4.因为(a+b)9的展开式中有10项,所以中间两项的二项式系数最大,这两项分别为C_9^4a5b4=126a5b4,C_9^5a4b5=126a4b5.答案:1.70a4b4 126a5b4与126a4b5 2. A=C_n^0+C_n^2+C_n^4+…与B=C_n^1+C_n^3+C_n^5+…的大小关系是( )A.A>B B.A=B C.A<B D.不确定 解析:∵(1+1)n=C_n^0+C_n^1+C_n^2+…+C_n^n=2n,(1-1)n=C_n^0-C_n^1+C_n^2-…+(-1)nC_n^n=0,∴C_n^0+C_n^2+C_n^4+…=C_n^1+C_n^3+C_n^5+…=2n-1,即A=B.答案:B
人教版高中数学选修3一元线性回归模型及其应用教学设计
1.确定研究对象，明确哪个是解释变量，哪个是响应变量；2.由经验确定非线性经验回归方程的模型；3.通过变换，将非线性经验回归模型转化为线性经验回归模型；4.按照公式计算经验回归方程中的参数，得到经验回归方程；5.消去新元，得到非线性经验回归方程；6.得出结果后分析残差图是否有异常 ．跟踪训练1.一只药用昆虫的产卵数y与一定范围内的温度x有关，现收集了6组观测数据列于表中： 经计算得： 线性回归残差的平方和: ∑_(i=1)^6?〖(y_i-(y_i ) ?)〗^2=236,64,e^8.0605≈3167.其中 分别为观测数据中的温度和产卵数，i=1,2,3,4,5,6.(1)若用线性回归模型拟合，求y关于x的回归方程 (精确到0.1）；(2)若用非线性回归模型拟合，求得y关于x回归方程为 且相关指数R2＝0.9522． ①试与(1)中的线性回归模型相比较，用R2说明哪种模型的拟合效果更好 ?②用拟合效果好的模型预测温度为35℃时该种药用昆虫的产卵数.(结果取整数).
新人教版高中英语必修3Unit 1 Festivals and Celebrations-Reading and Thinking教学设计
The topic of this part is “Discover the reasons for festivals and celebrations.The Listening & Speaking & Talking part aims at talking about the experiences and feelings or emotions about the festivals and celebrations. This section aims at detecting the reason why the people celebrate the festivals, the time, the places, the types and the way of celebrations. It also explains why some traditions in the old celebrations are disappearing, like the firecrackers in the big cities and some new things are appearing like the prosperity of business or commerce. 1. Students can talk about what festivals they know and the reasons and the way of celebrating them.2. Students should learn the reading skills such as the headline and get the topic sentences, the structures of articles.3. Students can understand the past, the present situation of some festival around the world and why there are some changes about them. 4. Students can have the international awareness about the festivals.1. Students should learn the reading skills such as the headline and get the topic sentences, the structures of articles.2. Students can understand the past, the present situation of some festival around the world and why there are some changes about them.Step 1 Lead in---Small talkWhat festival do you like best ? Why ?I like the Spring Festivals because I can set off the fireworks, receive the lucky money and enjoy the Gala with my families.Step 2 Before reading---Pair workWhy do people celebrate different festivals ?The Spring Festivals is to celebrate the end of winter and the coming of spring and new life.The Mid-autumn Day is to celebrate the harvest and admire the moon.
新人教版高中英语必修3Unit 1 Festivals and Celebrations-Reading for writing教学设计二
Step 3 Analyzing article structureActivity 31. Teachers raise questions to guide students to analyze the chapter structure of this diary and think about how to describe the festival experience. (1)What should be included in the opening/body/closing paragraph(s)?(2)How did the writer arrange his/her ideas?(3)What kind of interesting details did the writer describe?(4)How did the writer describe his/her feelings/emotions during the event?2. Students read and compare the three sentence patterns in activity 2. Try to rewrite the first paragraph of the diary with these three sentence patterns. After that, students exchange corrections with their partners. Such as:●This was my first time spending three days experiencing the Naadam Festival in China’s Inner Mongolia Autonomous Region and it was an enjoyable and exciting experience. ●I'll never forget my experience at the Naadam Festival because it was my first time to watch the exciting Mongolian games of horse racing, wrestling, and archery so closely. ●I'll always remember my first experience at the Naadam Festival in China’s Inner Mongolia Autonomous Region because it was so amazing to spend three days witnessing a grand Mongolian ceremony. Step 4 Accumulation of statementsActivity 41. Ask the students to read the diary again. Look for sentences that express feelings and emotions, especially those with the -ing form and the past participle. Such as:● …horse racing, wrestling, and archery, which are all so exciting to watch. ● some amazing performances● I was surprised to see…● I was a little worried about. . . ● feeling really tiredOther emotional statements:●I absolutely enjoyed the archery, too, but the horse races were my favourite part. ●I'm finally back home now, feeling really tired, but celebrating Naadam with my friend was totally worth it. ●He invited me back for the winter to stay in a traditional Mongolian tent and cat hot pot. I can’t wait!2. In addition to the use of the -ing form and the past participle, the teacher should guide the students in the appreciation of these statements, ask them to memorize them, and encourage them to use them reasonably in writing practice.
新人教版高中英语必修3Unit 2 Morals and Virtues-Discovering Useful Structure教学设计
1. 表示时间。Hearing these stories, I’m skeptical about the place. = When I heard these stories. . . 2. 表示原因。Not knowing his address, I can’t send this book to him. = Because/Since/As I don’t know his address. . . 3. 表示结果。His father died, leaving him a lot of money. =. . . and left him a lot of money4. 表示条件。Going straight down the road, you will find the department store. = If you go straight down the road. . . 5. 表示让步。Being tired, they went on working. =Although they were tired. . . 6. 表示行为方式、伴随情况或补充说明。He lay on the grass, staring at the sky for a long time. =. . . and stared at the sky for a long time注意：非谓语动词作状语时, 如所提供的动词不能和句子中的主语保持一致, 动词-ing形式必须有自己的逻辑主语, 通常由名词或代词来担任, 这就是独立主格结构。The last bus having gone, we had to walk home. (having gone的逻辑主语是the last bus, 而不是we)Weather permitting, the football match will be played on Friday. (permitting的逻辑主语是time, 而不是the football match)Step 7 Practice1. ________(study) hard, you are sure to get first prize. 2. People use plastic in their daily life, _______(leave) large amounts of waste. 3. ________(work) hard at your lessons, you are to succeed. 4. The old man, ____________(work) abroad for twenty years, is on the way back to his motherland. 5. ______________(finish) his homework, he was playing on the playground. Answers: 1. Studying 2. leaving 3. Working 4.having worked 5. Having finishedStep 8 HomeworkFinish the homework on Page 22.
新人教版高中英语必修3Unit 2 Morals and Virtues-Reading for Writing教学设计
1. 这个寓言是一个关于一位国王古寓言。 The fable is an old fable about a king.2.作者用这个故事让读者对于社区的问题负有个人责任的必要印象深刻。The author used the story to impress upon readers with the need to take personal responsibility for problems in the community.3. 这个故事十分成功的实现了它的目的。The story was quite successful in achieving its purpose.Step 7 WritingPlease write a review of the story according the outline above.The fable is an old fable about a king who thought his people are lazy, so he put a large stone in the middle of the road and hides and waited to see if anyone will try to move it.The author used this story to impress upon readers with the need to take personal responsibility for problems in the community. The story was quite successful in achieving its purpose, and I liked it because it had a clear moral.However, while the moral of the story is clear, the actions of the king seemed pointless to me, because none of the characters in the story learnt anything. For this reason, I think there are better stories that can be used to impress upon people with the need for personal responsibility.Step 8 Pair workExchange drafts with a partner. Use this checklist to help your partner revise his/her draft.1. Does the writer give a short description of the story ?2. Does the description include the most important details of the story ?3. Does the writer give his or her opinion about the character or their actions ?4. Is the review well-organised ? 5. Does the writer use the -ing form as the adverbial correctly in the writing ?6. Are there any grammar, spelling, or punctuation errors ?Step 9 HomeworkPut up your revised draft in the classroom or read it to your class.
新人教版高中英语必修3Unit 4 Space Exploration-Discovering Useful Structure教学设计
The theme of the section is “Describe space facts and efforts to explore space”. Infinitives are one of non-finite verbs, as the subjects, objects, predicative, attributes and adverbials. This unit is about space exploration, which is a significant scientific activity, so every scientific activity has strong planning. Therefore, using the infinitives to show its purpose, explanations or restrictions is the best choice.1. Learn the structure, functions and features of infinitives.2. Learn to summarize some rules about infinitives to show purpose and modify.3. Learn to use infinitives in oral and writing English. 1. Learn the structure, functions and features of infinitives.2. Learn to summarize some rules about infinitives to show purpose and modify.3. Learn to use use infinitives in oral and writing English.Step 1 Lead in---Pair workLook at the following sentences and focus on the italicized infinitives. In pairs, discuss their functions. 1. I trained for a long time to fly airplanes as a fighter pilot..(作目的状语)2. As we all know, an astronaut needs to be healthy and calm in order to work in space..(作目的状语)3. First of all, you must be intelligent enough to get a related college degree..(作目的状语)4. Some scientist were determined to help humans realise their dream to explore space..(作定语)5. On 12 April 1961, Yuri Gagarin became the first person in the world to go into space..(作定语)Summary:1. 不定式的结构：to+do原形。2. 分析上面的句子，我们知道在描述太空探索时，动词不定式不仅可以用来表目的，还可以用来作定语，表修饰。
新人教版高中英语必修3Unit 4 Space Exploration-Reading For Writing教学设计一
另一方面，其余的人反对这个计划，因为它可能会导致一些不好的影响。7.I hold the belief that space exploration not only enable us to understand how the universe began but also help us survived well into the future.我坚信探索太空不仅能够使我们了解宇宙的起源而且能够帮助我们更好地走进未来。8.I think we should spend more time and money exploring space so as to provide new and better solutions to people's shortterm and longterm problems.为了给人类的短期和长期问题提供更新和更好的解决方法，我认为我们应该花更多的时间和金钱来探索太空。9．From my point of view，it is wrong of young people to depend on their telephones too much，which may do harm to both their physical and mental health.在我看来，年轻人过度依赖手机是不对的，因为它们可能会对他们的身心健康都有害。最近你班同学就“人类是否应该进行宇宙探索”这个问题进行了激烈的讨论。有人认为，探索宇宙不仅让人类更好地了解宇宙的发展，还可以用来指导农业生产，以及把一些探索太空的高新技术用于现实生活；也有一些人认为探索太空花掉了大量的人力物力；影响了人们的生活水平。请你根据以下情况写一篇报告并发表自己的观点。注意：1.写作内容应包括以上全部要点，可适当发挥，使上下文连贯；
新人教版高中英语必修3Unit 5 The Value of Money-Listening &Speaking教学设计
Step 4: Listen again and decide if the following statements are true (T) or false (F).1 It was the first time Chen Liyan's story was reported. T口 F口2 Chen found 10,000 yuan in a small plastic bag in Taiyuan railway station口 F口3 Wang Zheng apologized to Chen because he couldn't offer her more money. T口 F口4 Chen took out a large loan to cure her daughter, T口 F口5 Wang set up a fundraising website for Chen's daughter after Chen told him about her situation. T口 F口Step 5：After listening, discuss the questions.1 What kind of person do you think Chen Liyan is?Chen Liyan is generous and honest because she returned a large sum of money to the owner.2 Did Chen return the money because she didn't need it?No. She returned the money because it was the right thing to do. Evidence for this is that she refused to accept the reward money because she felt that it had not been earned. 3 Is it common for people to do what Chen did?It depends on the culture. In some countries it is quite common to return money that has been found. In other countries, people believe "Finders are keepers!" 4 How did Wang Zheng feel about the return of his money?He must have been very happy and relieved to have gotten his money back. We know this because he thanked Chen repeatedly and even offered her a reward.5 Why did Ma Dongbao tell Wang about Chen's family?He must have had great sympathy for Chen and her daughter and wanted to help them.'We know this because he arranged help for them. 6 How did the news reporter feel about Chen's actions?The news reporter felt that it showed that money wasn't the most important thing in life. We know this because the reporter told us that this is what Chen believes. and then said, “that's a great attitude to take."
新人教版高中英语必修3Unit 5 The Value of Money-Reading for Writing教学设计二
2. 您能看到, 我头发太长了。You can see that my hair is much too long.3. 无论什么时候, 只要您想回来就回来。Please come back whenever you want.4. 您仅有很少的头发要理! You only have too little hair to cut !5. 为您服务是我的荣幸！It is my honour to serve you!Step 9 Writing(Henry is walking down the street when he sees a sign for a place that cuts hair. He decides to have it cut. )H=Henry B=BarberH: Good afternoon, I’d like to have my hair cut, if I may. (The barber looks at Henry’s hair and continues cutting another man’s hair. ) Er, I’d really like a haircut. As you can see it’s much too long. B: (in a rude manner) Yes, I can see that. Indeed, I can. H: Fine, well, I’ll have a seat then. (He sits in one of the barber’s chairs. The barber turns to look at Henry. )B: It’s quite expensive here, you know! Are you sure you can afford it?H: Yes. I think so. (After his hair is cut, the barber tells Henry how much he must pay. Henry shows the barber the bank note. )B: Why Mr. . . (looks shocked)H: Adams. Henry Adams. I’m sorry. I don’t have any change. B: Please don’t worry! (wearing a big smile) Nothing to worry about! Nothing at all! Please come back whenever you want, even if you only have too little hair to cut! It will be my honour to serve you!Step 10 Pair workExchange drafts with a partner. Use this checklist to help your partner revise his/her draft.1. Are all the elements of a play included and in good order ?2. Do the character use suitable language ?3. Are the stage directions clear and useful ?4. Is the plot clear and exciting enough ?
新人教版高中英语选修2Unit 1 Science and Scientists-Learning about Language教学设计
Step 7: complete the discourse according to the grammar rules.Cholera used to be one of the most 1.__________ (fear) diseases in the world. In the early 19th century, _2_________ an outbreak of cholera hit Europe, millions of people died. But neither its cause, 3__________ its cure was understood. A British doctor, John Snow, wanted to solve the problem and he knew that cholera would not be controlled _4_________ its cause was found. In general, there were two contradictory theories 5 __________ explained how cholera spread. The first suggested that bad air caused the disease. The second was that cholera was caused by an _6_________(infect) from germs in food or water. John Snow thought that the second theory was correct but he needed proof. So when another outbreak of cholera hit London in 1854, he began to investigate. Later, with all the evidence he _7_________ (gather), John Snow was able to announce that the pump water carried cholera germs. Therefore, he had the handle of the pump _8_________ (remove) so that it couldn't be used. Through his intervention，the disease was stopped in its tracks. What is more, John Snow found that some companies sold water from the River Thames that __9__________________ (pollute) by raw waste. The people who drank this water were much more likely _10_________ (get) cholera than those who drank pure or boiled water. Through John Snow's efforts, the _11_________ (threaten) of cholera around the world saw a substantial increase. Keys： 1.feared 2.when 3. nor 4.unless 5.that/which 6.infection 7.had gathered 8.removed 9.was polluted 10.to get 11. threat
新人教版高中英语选修2Unit 1 Science and Scientists-Using langauge教学设计
This happens because the dish soap molecules have a strong negative charge, and the milk molecules have a strong positive charge. Like magnets, these molecules are attracted to each other, and so they appear to move around on the plate, taking the food coloring with them, making it look like the colors are quickly moving to escape from the soap.Listening text:? Judy: Oh, I'm so sorry that you were ill and couldn't come with us on our field trip. How are you feeling now? Better?? Bill: Much better, thanks. But how was it?? Judy: Wonderful! I especially liked an area of the museum called Light Games.it was really cool. They had a hall of mirrors where I could see myself reflected thousands of times!? Bill: A hall of mirrors can be a lot of fun. What else did they have?? Judy: Well, they had an experiment where we looked at a blue screen for a while, and then suddenly we could see tiny bright lights moving around on it. You'll never guess what those bright lights were!? Bill: Come on, tell me!? Judy: They were our own blood cells. For some reason, our eyes play tricks on us when we look at a blue screen, and we can see our own blood cells moving around like little lights! But there was another thing I liked better. I stood in front of a white light, and it cast different shadows of me in every color of the rainbow!? Bill: Oh, I wish I had been there. Tell me more!? Judy: Well, they had another area for sound. They had a giant piano keyboard that you could use your feet to play. But then, instead of playing the sounds of a piano, it played the voices of classical singers! Then they had a giant dish, and when you spoke into it, it reflected the sound back and made it louder. You could use it to speak in a whisper to someone 17 meters away.? Bill: It all sounds so cool. I wish I could have gone with you? Judy: I know, but we can go together this weekend. I'd love to go there again!? Bill: That sounds like a great idea!
